Summary: The success of a gene therapy for blindness caused by a genetic mutation paves the way for gene therapies which treat other forms of blindness as well as similar treatments which treat other diseases. [This article first appeared on the Longevity Facts website. Author: Brady Hartman. ]
In a historic move, the FDA on Tuesday approved a pioneering gene therapy for a rare form of blindness, the first such treatment cleared in the United States for an inherited disease.
The approval signals a new era for gene therapy, a field that struggled for decades to overcome setbacks. The field has started bearing fruit as of late – as researchers announced the phenomenal results of a gene therapy trial for hemophilia -and is also developing promising treatments for sickle-cell anemia and a myriad of other inherited diseases. However, the novel treatments are likely to carry astronomical prices, a prospect already worrying consumer advocates and patients.
Spark Therapeutics, which makes the gene therapy for blindness has not announced a price for the treatment. Analysts speculate it could be as high as $1 million for both eyes.
Earlier this year, the FDA approved two other gene therapies for cancer treatment. Both are forms of CAR T cell therapy, a cancer immunotherapy that targets blood cancers. CAR T cell therapy involves removing immune cells from patients, genetically reprogramming them to better attack cancer and returning them to the patients.
The newly approved gene therapy is for a rare form of blindness called Leber Congenital Amaurosis (LCA), an inherited degenerative retinal disease characterized by severe loss of vision at birth. LCA is a rare disorder, affecting about 1 in 80,000 people. There are no other FDA-approved treatments available for inherited retinal diseases.
The treatment, called voretigene neparvovec (brand name: Luxturna), performed well in the randomized and controlled phase III clinical trial. Out of 29 patients treated with the gene therapy, 27 experienced meaningful improvements in their vision, enough that they could navigate a maze in low to moderate light. The successful results of the gene therapy clinical trial marked the fruitful end of years of research.
While the gene therapy does not represent a cure or result in perfect vision, it can substantially improve eyesight, say researchers. However, it allows patients to see shapes and light and enables them to walk around without a guide dog or cane. Treated patients show an improvement in light sensitivity and peripheral vision, two common visual deficits experienced by people with LCA. Scientists are unsure how long the treatment will last. So far, most of the treated with the gene therapy have maintained their vision for two years.
How Luxturna’s Gene Therapy Works
Leber Congenital Amaurosis can be caused by any combination of 19 different genes. The most common cause is a defect in the RPE65 gene which produces a protein of the same name. The RPE65 protein helps the cells that nourish the retina, called the retinal pigment epithelial cells (RPE), to process vitamin A. The RPE cells of people who have this mutation do not produce enough vitamin A, an essential nutrient that allows visual proteins to sense light.
Repairing the genetic defect requires delivering a DNA segment with a healthy copy of the RPE65 gene packaged in a virus vector. Doctors use a harmless virus that is genetically modified to carry a healthy version of the gene into the retina. Physicians then inject billions of these genetically-modified modified viruses into both of the patient’s eyes.
Paving the Way for Other Forms of Gene Therapy
FDA approval of Luxturna is a significant milestone could pave the way for other gene therapies that could eventually treat the more than 225 genetic defects known to cause blindness. For example, gene therapy could potentially restore vision in age-related macular degeneration (AMD), more common forms of vision loss. Moreover, gene therapy could be used to treat retinitis pigmentosa, an inherited retinal disease caused by a genetic defect.
Approval of Luxturna’s product paves the way for gene therapies to treat diseases other than blindness, according to FDA Commissioner Scott Gottlieb, M.D, who said in a statement
“Today’s approval marks another first in the field of gene therapy — both in how the therapy works and in expanding the use of gene therapy beyond the treatment of cancer to the treatment of vision loss — and this milestone reinforces the potential of this breakthrough approach in treating a wide-range of challenging diseases.”
Scientists hope that gene therapy can be used to treat other forms of blindness, and eventually other diseases.
Related Articles on Gene Therapy
- Learn more about gene editing in this video on the Future of Medicine.
- Microsoft’s Gates Foundation to Genetically Engineer Laser Lit Mosquitos.
- Learn more about the history of the LCA gene therapy for blindness.
- MIT researchers discover how to do CRISPR gene editing with nanoparticles.
- Watch a video on CRISPR 2.0, showing new ways to edit genes.
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FDA News Release. “FDA approves novel gene therapy to treat patients with a rare form of inherited vision loss” FDA. Link.
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